The present invention relates to a paper feeder that is incorporated in an image forming apparatus such as copier, multifunctional apparatus, facsimile equipment and/or the like, and to an image forming apparatus including the same.
In an automatic document feeder, there is provided a sensing member (actuator) that senses, when a paper sheet (document) is set at a predetermined position on a paper sheet stacking tray, that the paper sheet is set. That the paper sheet is set is sensed when a front edge of the paper sheet that comes into contact with the actuator causes the actuator to be swung toward a paper feed direction.
In order to adjust a timing of sensing properly depending on sizes in width of paper sheets of documents, a paper feeder that is disclosed in Japanese Patent Unexamined Publication No. 2004-51253 bulletin, for example, is provided with a first actuator that is adapted for paper sheets of relatively large sizes including normal paper sizes, and a second actuator that is disposed at an inner position than the first actuator in width direction and adapted for paper sheets of relatively small sizes.
Edges of ends on sensing sides (upstream sides in the paper feed direction) of the first actuator and the second actuator are parallel with each other, and incline at a same angle, while the end on the sensing side of the second actuator that is adapted for the paper sheets of small sizes is located on a downstream side, in the paper feed direction, from the end on the sensing side of the first actuator that is adapted for the paper sheets of large sizes including normal paper sizes. The first actuator and the second actuator are supported by a same swing shaft in such a manner that when either one of the actuators is swung, then operating together therewith, the other is also swung.
Also, it is disclosed that with the second actuator that is adapted for the paper sheets of small sizes being disposed within widths of business cards the above-mentioned paper feeder can deal with documents of sizes of business cards.
However, with the second actuator being disposed within the widths of business cards, although it can easily sense the business cards that are made of thick paper, there has been a problem that sensing mistakes occur in such cases as when a document of a normal paper size that is to be sensed by the first actuator is set but a front edge of the paper sheet is curled then the first actuator is not swung because the paper sheet curls up along the end on the sensing side of the first actuator nor does the front edge of the paper sheet come into contact with the second actuator of which end on the sensing side is located on the downstream side from the first actuator in the paper feed direction.
The present invention is directed to providing a paper feeder and an image forming apparatus including the same that is capable of surely sensing even a paper sheet of a normal paper size that is curled by using a first actuator that is adapted for paper sheets of large sizes including normal paper sizes and a second actuator that is disposed within widths of business cards.